Use of dialkyl glutarates in vinylidene resins



United States Patent iOfilice v Patented Nov. 4,1958

USE OF DIALKYL GLUTARATES VINYLIDENE RESlNS Robert J. Reid, CanalFulton, William Mayo Smith, Jr., Cuyahoga Falls, and Byron H. Werner,Akron, Ohio, assignors to The Firestone Tire & Rubber Company, Akron,Ohio, a corporation of Ohio No Drawing. Application February 23, 1954Serial No. 412,074

9 Claims. (Cl. 260-313) ing temperature below the critical range withouthaving any undesirable effect on the products obtained.

Such resins are characterized by crystalline behavior, i. e., they fusesharply to form relatively fluid melts. On quenching and orienting, theextruded filaments'and films are crystalline in character. A syndrome ofthis crystalline habit is the recalcitrance of these resins tocompounding: The macromolecules of these resins prefer contact with eachother and tend to reject any foreign substances such as plasticizers andthe like. In the random structure obtained without orientation any addedingredient of limited compatability, such as the processing aids of thisinvention, is retained in larger percentages than is possible in thestretched or oriented products. On stretching, the tendency towardexudation or spewing is considerably increased. In orienting films andfilaments of vinylidene resins they are stretched to several times theiroriginal length, and ordinarily until there is a sharp rise in themodulus. It is difiicult to provide suitable processing aids which donot exhibit an undesirable spew or bloom on the surface of the orientedproducts and which in addition possess good heat and light stability orwhich at least are not detrimental to such stability.

Thus, the problem of providing processing aids for these crystallineresins is complicated not only by the fact that they tend to reject andspew the majority of conventional plasticizers, but, because the resinsare extruded as hot melts at temperatures in the neighborhood of, forexample, 170 C., many conventional resin-compounding ingredients tend todecompose or react with other compounding ingredients which are presentwhen the resins are maintained in a molten state immediately prior toand during extrusion.

The crystalline resins to which the processing aids of this inventionare added include both homopolymers of vinylidene chloride andcopolymers thereof with not more than substantially 15 percent of otherethylenically unsaturated compounds copolymerizable therewith. Thecopolymers contain at least substantially 85 percent of vinylidenecholoride. Suitable comonomers for the copolymerization include, forexample, vinyl chloride, vinyl fluoride, vinylacetate, styrene, acrylicand methacrylic esters such as methyl methacrylate, ethyl meth acrylateand the like, acrylonitrile, vinyl-type ethers and ketones such asmethylvinyl ether, methylvinyl ketone and related compounds such asmethylisopropenyl ketone and the like. For a more complete list ofcompounds known to copolymerize with vinylidene chloride to produceresins which can be plasticized as herein described see Krczil, KurzesHandbuch der Polymerisationstechnik, vol. II, Mehrstoffpolymerization,Edwards Bros., Inc, p. 739, the items indented under fvinylidenechlorid.

The processing aids of this invention are the dialkyl glutarates, thealkyl groups of which each contain one to three carbon atoms. They haveexcellent light stability and good heat stability as well as good spewresistance. They arenon-toxic, non-allergenic, and relatively odorless.In addition, they do not appreciably in crease the tendency of orientedfilms or filaments to shrink when exposed to elevated temperatures.

Compounding and testing With regard to the use of the processing'aids, asmall amount, in the range of 3 to 8 percent. or up to 10 percent basedon the weight of the'resin will generally be found most satisfactory.Less than 3 percent may be used in admixture with another processingaid. Such percentages will be stably retained within the resin in thefinished oriented article. The lower membered esters show a lessertendency to spew (greater compatability with the resin) than the highermembered glutarate esters. Thus, dimethyl glutarate can be used ingreater amounts than di-n-propyl) glutarate without showing a spewtendency. In no case will more than about 10 percent of the processingaid be employed in a vinylidene resin because such larger amounts areincompatible and exude to the surface of oriented products produced fromvinylidene polymeric resins containing percent or more of vinylidenechloride.

The dialkyl glutarates can be employed with the epoxy heat stabilizerssuch as glycidyl-phenylether, the mono-, di-, tri-, tetra-, andpenta-chlorinated derivatives of phenoxypropene oxide, polymeric phenoxycompounds prepared from various dihydroxy phenols and epichlorhydrin,etc. Likewise, they can be employed with esters of salicylic acid whichare light stabilizers, such as phenyl salicylate, 4-tert-butylphenylsalicylate, 4-octyl phenyl salicylate, Z-methyl phenyl salicylate,4-chloro phenyl salicylate, 3-methyl phenyl salicylate, 4-t-amyl phenylsalicylate, 4-nonyl phenyl salicylate, 2-octyl-4- methyl salicylate,2-isopropyl salicylate, nonyl salicylate,

Parts by weight Crystalline resinous copolymer of vinylidene chlorideand vinyl chloride (85:15) Glycidyl phenyl ether -I 0 or 2 4-t-butylphenyl salicylate 0or2 Processing aid 8 The additives were ball milledwith the resin, and sam ples tested for heat stability, light stabilityand spew I according to the methods given below:

Heat stability Five grams of the composition to be tested were chargedinto a compression mold of Hastelloy C (a 55/ 20/ 6/ 14/5 Ni/Mo/Fe/Cr/Walloy) in the form of a cylinder 1.25 inches in diameter. Thevmoldingcycle was (1 Heat for three minutes with steam at 120 lbs./ sq. in. andmold pressure of 1000 lbs/sq. in;

(2) Water (1001 for two minutes under 1000 lbs/sq. in. mold pressur a(3) Eject from the press. I

The resultant cylindrical button (1.25 inches in diameter and .l2,5..188inch in height) was then cut into sector-shaped specimens which wereplaced in a forceddraft oven at 180 C. Specimens were removed atintervals of 10, 20, and 30 minutes after placing in the oven, and thebehavior of the specimens on the test as a whole was rated by theoperator.

Light stability A plague of the compounded resin was pressed betweencellophane (regenerated cellulose) sheets in a Carver press at 180 C.,using approximately 1.5 grams of resin,

10 seconds preheat, and 15 seconds with the minimum a pressure (pressureindicator just OK zero). The plaque was quenched in cold waterimmediately and an approximately inch wide strip was cut from theplaque, the cellophane removed, and the strip oriented to its limit.

The oriented strips were placed in glassine bags under mild pressure sothat contact of the strips with the bag was assured. Any exudation ofplasticizer could then be noted as an oily streak on the glassine. Testswere carried out at room temperature and at 50 C., the latter conditiontending to accentuate any migration of plasticizer.

Using the glutarates of this invention, no spew was observed in thistest after 56 days at room temperature. With dioctyl phthalate insteadof a glutarate definite spew occurred after pne day.

Test results It was found that the use of dimethyl, diethyl, and thedipropyl glutarates do not adversely affect the heat and light stabilityof the resin compositions. In fact, it was often observed that thedeletion of the 'glycidyl phenyl ether :(used as a heat stabilizer)and/or the 4-t-butyl phenyl salicylate (used as a light stabilizer) Waspartially compensated for by the various processing aids. Glutarates inthe range of dimethyl to dipropyl glutarates were chosen as processingaids because these materials do notshow adverse spew under theaforementioned conditions. The light and heat stability of these estersis entirely satisfactory. However, esters higher than a dipro- ,ofvinylidene chloride are somewhat less compatible wifla the processingaids than copolymers containing as much as 15 percent of vinyl chlorideof other monomer.

Extrusion Tests were. conducted using various processing aids with 4 to,8 parts by Weight ofthe processing aid, together With 2 parts glycidylphenyl ether and 2 parts phenyl salicylate as light and heatstabilizers. were carried out in conventional screw-type machines, the

molten polymer being forced through dies to form E laments which werethen quenched by passage througha water bath and cold-drawn some 400percent by passage.

over differential speed rolls.

With as little as four parts'of dimethyl, diethyl, or a' dipropylglutarate smooth filaments are produced readily when exposed to Floridasunshine. They have good heat stability. Extrusions carried out withconventional plasticizers such as di-octylphthalate required at least 8parts plasticizer to give desirable extrusion characteristics and suchfilaments onstorage in all cases exuded the plas ticizer.

The processing aids of this invention lower the melt 1.,

temperature of the resin, allowing extrusions to take place withoutdecomposition. The extruded products are smooth and of uniform diameter,and. are free of spew after orientation.

What we claim .is: s V 1. In the process of extruding and orienting acrystalline polymeric resin selected from the group consisting ofhomopolymers of vinylidene chloride and copolymers thereof with up to 15percent of other ethylenically unsaturated monomer, the improvementwhich comprises extruding and orienting the molten resin while admixedwith a dialkyl glutarate, as a processing aid, the glutarate being fromthe class consisting of dimethyl, diethyl and dipropyl glutarates,whereby a non-exuding extruded, oriented product is obtained, the amountof the glutarate being substantial but not in excess of about 10percent, said percentages referring to percentages by weight of thepolymeric resin.

2. The process of claim 1 in which the dialkyl gultarate is die thylglutarate. V

3. The process of claim 1 in which an epoxy heat stabilizer and a lightstabilizer are used in the molten resin, the light stabilizer being anester of salicyclic acid;

4. A resin composition which includes'a crystalline V polymeric resinselected from the group consisting of homopolymers of vinylidenechloride and copolymers thereof with up to 15 percent of otherethylenically unsaturated monomer, and as a processing aid a dialkylglutarate from the class consisting of the ,dimethyl, di-

ethyl and dipropyl 'glutarates, the amount of the glutarate beingsubstantial but not in excess of about 10 percent,

said percentages referring to percentages by weight of the polymericresin. 7

5. The resin composition of claim 4 in which theproccssing aid isdiethyl glutarate.

6. The resin composition of claim 4 which contains an epoxy heatstabilizer and a light stabilizer which is an ester of salicylic acid.

7. A resin composition which includes a copolymer of substantially 85percent vinylidene chloride and 15-percent vinyl chloride, and asubstantial amount notin excess of 10 percent byweight, based on theweight of the copolymer, of an ester from the group consisting of di-'methyl to dipropyl glutarates, the glutarate being'a pro-r ccssing aid.for the extrusion of the resin.

8. The resin composition of claim '7 in which the ester is diethylglutarate.

9. The resin composition of claim 7 which contains an epoxyheatstabilizer and a light stabilizer which is an ester of salicyclicacid.

References Cited in the file of this patent UNITED STATES PATENTS e erusi ns Kvalnes Aug. 24, 19 27 UNITED STATES PATENT OFFICE CERTIFICATIONOF CORRECTION Patent No. 2,859,196 November 4 1958 Robert J.v Reid eta1. It is hereby certified that error appears in the above numberedpatent requiring correction and that the said Letters Patent shouldreadas corrected below.

Column 3 line 71 for "of other" read or other column 4 line 10 for "Thefilaments" read These filaments Signed and sealed this 10th day of April1962.

(SEAL) Attest:

ERNEST W. SWIDER DAVID L. LADD Attesting Officer Commissioner of Patents

4. A RESIN COMPOSITION WHICH INCLUDES A CRYSTALLINE POLYMERIC RESINSELECTED FROM THE GROUP CONSISTING OF HOMOPOLYMERS OF VINYLIDENECHLORIDE AND COPOLYMERS THEREOF WITH UP TO 15 PERCENT OF OTHERETHYLENICALLY UNSATURATED MONOMER, AND AS A PROCESSING AID A DIALKYLGLUTARATE FROM THE CLASS CONSISTING OF THE DIMETHYL, DIETHYL ANDDIPROPYL GLUTARATES, THE AMOUNT OF THE GLUTARATE BEING SUBSTANTIAL BUTNOT IN EXCESS OF ABOUT 10 PERCENT, SAID PERCENTAHES REFERRING TOPERCENTAGES BY WEIGHT OF THE POLYMERIC RESIN.